How come Carbon-13, one of the stable isotopes of Carbon, has an atomic mass of 13.00335 amu and not 13 amu? The nucleus of a Carbon-13 atom consists of 6
protons and 7 neutrons, so why shouldn't the atomic mass be 13? And, furthermore, if it isn't 13 amu, then why is it called Carbon-13? Why not Carbon-13.00335?
Basically, the amu of Carbon-13 is known as 13. Again, in some places, the atomic mass of Carbon-13 is given 13.00335 amu. And, whenever we try to get the weighted average of all the isotopes of Carbon, we use 13.00335 as the atomic mass of Carbon-13.
It is too confusing. Simply, horribly confusing!
Someone please help me! I know that it might be a difficult question to ask, but if some confusions are never solved, it will stay mysterious forever.
It's not just Carbon-13. There are many other isotopes.